Si Chi Anti-collision Car Laser Fog Lamp Bright Red LED Laser Rear Tail Indicator Fog DIY Lights Trailer Car Truck On rainy, foggy, sandstorm days, it works as a warning sign to effectively avoid traffic accidents that caused by driving too close. You can adjust the angle of the bulb to adjust the safe distance. It can also be used as vehicles' position warning and steering indicator at night. It will be helpful when you back your car into garage. It works by installing a red laser emitter at the back of car, which can generate a red fan-shaped beam in the air when bad days. when you turn it on sunny says, you can only see a red line on the road, so license plate still can be seen clearly. ng setting.